If the length of the resistance wire is increased by 10%.then find out the change in corresponding resistance.?
Hello Kusm,
I would try to explain you with a help of an example below.
Let the length of wire = 100 cm.
Let its area of cross section = a cm²
Then resistance R of wire= resistivity× 100/a….(1)
Length of wire after stretching = 110 cm
Let the new area of cross section = a' cm²
Volume of wire must be same before and after stretching, ie
100 a = 110 a' or a' = 10a/ 11 cm²
New resistance R'= (resistivity)×110× 11/10a= (resistivity)× 121/a …………….(2)
Dividing (2) by (1) we get,
R'/R = 121/100
( R' - R/R) = 121–100/100= 21/100
Therefore % change= 21% increase in resistance.
So I hope this solves your doubt and if you have any more doubt then you can comment down your query in the comments section.
All the best to you!
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